JPS59119487A - Coordinate reader - Google Patents

Abstract

PURPOSE:To ensure a uniform coordinate reading accuracy at any position on a tablet by reading each phase linear range of plural tablets through a processing circuit and using a large phase linear range formed by adding the phase linear ranges together. CONSTITUTION:The tablets 2 and 3 are connected each other, and a driving signal switching circuit 4 is used to supply the driving signal to the tablet 2. The phase 10 of a rotary magnetic field is detected via a pen 6. Then the circuit 4 is switched to obtain a phase 11 for the tablet 3 in the same way. Both phases 10 and 11 are supplied to a processing circuit 18 to calculate the linear ranges 10 and 11 as well as the phase difference theta1 between both ranges 10 and 11. Then the difference theta1 is added to the phase 11 to calculate a linear phase 17. The driving signal is supplied in time division to the tablets 2 and 3 from the circuit 4. When the phase on the tablet is detected by a detector 7, this detected phase and a connection point 16' are read out of a memory circuit 19 and compared with each other by the circuit 18. Thus the tablet is decided with the measured value. The obtained phase is read by a phase/coordinate converter 8 with the coordinates of high accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field of the Invention The present invention is directed to a large magnetic device that can read indicated position coordinates over a wide range with high precision. ? Relating to a combined type coordinate reading device.

(b) Technical background El (A mark reading device is a device that reads the coordinates of a pen placed on a tablet, and is used, for example, in graphical information processing/stems that play an important role in the fields of automatic design and drafting technology. It is something that can be done.

The coordinate reading device for this building uses an electrostatic coupling method,
A second electromagnetic induction method and a third ohmic method have been proposed, but the present invention is based on the second magnetic induction method, and in particular a type of IR position detection based on the phase of a rotating magnetic field. 0 (c) Prior Art and Problems In general, the coordinate reading device of the above type generates an alternating magnetic field whose phase differs depending on the position on the tablet, and the detection is detected by a pen-shaped magnetic field detector. A coordinate reading device for reading the indication-position coordinates of a magnetic field detector based on the phase has previously been proposed.

This can be done, for example, by arranging multiple coils in parallel and exciting them with different phases, so that over a wide area on the tablet, the position ji'i You (l(.

The position 1gi and X are identified by the detection phase θ of the magnetic field detector.

However, since the discrimination range of the detection phase θ is O~2π,
When reading the coordinates over a wide range, the resolution will be lower than when reading the coordinates in a narrow L1 range. However, since each coordinate reading device 1rl depends on the frequency (f) of the alternating current magnetic field and stopper, it is difficult to expand the coordinate reading range [111].

Therefore, there has been a proposal to increase the size by arranging a plurality of the same tablets and driving the tablets in a time-sharing manner, but this method has the disadvantage that reading accuracy deteriorates near the boundaries of each tablet.

A conventional coordinate reading device 1t will be described below with reference to FIG. The figure shows a block circuit of a coordinate area device for a plurality of tablets f:')rJ.

In FIG. 1, the coordinate reading device 1 includes two tablets 2,
A drive signal is alternately supplied to a plurality of coils arranged in parallel on the upper surface of each of the coils (see Fig. 2) in a time-sharing manner via a switch circuit 4 for switching the drive signal. A drive circuit 5 generates a rotating magnetic field on the top surface of the tablets 2 and 3, and a pen-shaped magnetic field detector (hereinafter referred to as a pen) 6 extracts a magnetic field coil 6' to detect the phase of the detected amount. A phase detector 7 and a phase converter that converts this phase into coordinates.
Consists of a coordinate converter.

In the case of the above-mentioned type of coordinate reading device, in the case of a pen type, there is a condition of a-h”-1 in order to minimize the error caused by the distance between the bears. Here, a is the phase change rate and indicates the phase change per unit length. .HI′i tablet coil to magnetic field detection coil 6
'0 indicates the effective height of the pen 6. From the above conditions, if the height h of the pen 6 is constant, then the X axis.

The phase change rate on the Y axis also needs to be the same. Therefore ■1
] For the sake of simplicity, if the arrangement of the X-axis and Y-axis coils is the same, the shape of the plane plate will be square.

Based on the above conditions, a coil as shown in FIG. 2 is constructed.

Figure 2 (a) shows a single-pipe coil 9 on/on the tablet placed to generate a rotating magnetic field with a phase that differs depending on the position.
It is a top view shown about -1 to 9-5.

The width of each coil and the spacing between the coils l! each one is a master,
Each coil has 〆I + 512113 as shown in the diagram.
A rotating magnetic field is generated on the tablet 2' by passing currents of +96, , and U with mutually different phases.

Fig. 2(b) shows that in order to perform the Drive coil 9'-
1 to 9'-5 are arranged orthogonally, and the widths of these coils and the spacing between the coils are the same as those of the coils 9-1 to 9-5 in FIG. ν(a), as shown.

A current is applied to the coils 9-1 to 9-5 to equalize the phases of 1 to 9, and the coils 9'-1 to 9'-5 are energized to have the same phase.
Two-dimensional coordinates can be read on the tablet 2' by applying a current of 1 L having a phase of ~15'. For convenience of instruction, the one-dimensional coordinate reading K of the X-axis will be explained unless otherwise specified.

The respective tablets 2 and 3 of the coordinate reading device 1 configured as described above are connected to the respective end portions 2 and 3 as shown in FIG. 3(1).
1 and 31, the respective phases are measured, and the phase characteristics shown in FIG. 3 (If) are obtained. In the figure, the vertical axis shows the phase, and the horizontal axis shows the X coordinate. 10 indicates the phase linear range of tablet 2, and 11 indicates the phase linear range of tablet 3. 12.14 and 13.15fd This shows the phase characteristics of the end portions of tablets 2 and 3, in which linearity has been lost. 'Since the accuracy of reading the locus coordinates is reduced, the tablets 2 and 3 cannot be used as one large tablet.

(d) Object of the Invention In order to solve the above-mentioned drawbacks, it is an object of the present invention to provide a coordinate reading device that connects a plurality of tablets and uses these tablets in a phase linear range.

(e) Structure of the Invention In order to achieve the above-mentioned object, the present invention provides a tablet having a plurality of coils arranged in parallel on a flat plate, and a plurality of drive signals having mutually shifted phases. an alternating current magnetic field generator that forms a rotating magnetic field with a different phase above the tablet according to the position of the tablet by energizing each of the plurality of coils; Detect the phase of the rotating magnetic field using a magnetic field detector that detects the grinding field and the output from the magnetic field detector manually, and set the position f6 of the magnetic field detector written on the tablet marked 1'1■'i, fLllk'. In the coordinate reading device which has a processing circuit, connects a plurality of the tablets, and dispatches the tablets in a time-division manner, the mutual connection points of the & number of tablets are determined by the phase plane of each tablet. The present invention is characterized by comprising means for determining a line range, and means for storing the connection points, correcting the phase positional relationship of the tablets, and reading a comprehensive phase linear range of the plurality of tablet tablets.

I will explain based on this.

FIG. 4 (ri) shows a state in which the tablets 2 and 3 are connected, and a part of the right end of the tablet 2 and a part of the left end of the tablet 3 shown in FIG. 3 are overlapped.

FIG. 4(t) shows the connection condition of the tablets.
4 with the dashed line 16. and phases 10 and 11
When the phase difference Crt is added to the phase 11, the junction point 16' of both phase linear ranges 10 and 11 as shown in FIG. 4(I) is obtained.
A linear phase 17 coupled with is formed.

FIG. 5 shows a block circuit diagram of a coordinate reading device that realizes the linear phase characteristic shown in FIG. 4(2).

In FIG. 5, the tablets 2 and 3 are connected as shown in FIG. The phase of the rotating magnetic field is detected by the phase detector 7 via the bevel 6, and the phase 1Otl- shown in Fig. 4 (Cr) is detected. Next, the switch circuit 4 is switched to supply a drive signal to the tablet 3, and the phase characteristics shown at 11 in FIG. 4(1) are obtained in the same manner as described above. This phase 10.11 is input to the processing circuit 18, and the phase linear range 10.
．． 11 and the phase difference θ1 between the two are calculated, and the processing circuit 18 further calculates the phase difference θ1 between the phase 11 and the phase difference θ1 based on the program.
1 is added to calculate the linearity 17 shown in FIG.

Next, a drive signal is supplied to the tablet 2 or 3 from the switch circuit 4 in a time-sharing manner, and when the phase on the tablet 2 or 3 is detected by the phase detector 7 via the pen 6, the detected phase and the connection point 16' shown in Figure 4(I).
is from memory circuit 19! ? I'a extracted processing circuit 1
Compared with 8, the measurement value of Tablet No. 1-2 or Tablet 3
The measured value is determined, and the measurement result is included in the linear range shown in FIG. 4 (G).

The phase thus obtained is read into highly accurate coordinates by the phase/body converter 8.

Next, another embodiment suitable for increasing the size of the tablet of the present invention will be described. The gist is the following energization.

The same driving current f:i for the X-axis and Y-axis of the tablet
The tablet's height and width ratio is square with a 1:1 ratio. As tablets have become larger, we have achieved this goal by using 4,119 tablets as a base.

However, for normal office paper or displays, rectangular shapes are used for ease of viewing, and in order to achieve 0 coils, a rectangular tablet is required, so each of the vertical and horizontal axes is Placement? The pitch of the 1" coils, the interval between coil conductors, and the size of the coil conductors are made equal, and the number of coils is arranged equal to the ratio of the length and breadth of the tablet.

Figure 6 shows another implementation U configured based on the above requirements.
tablet shown.

In Figure 6, the dimensions of the vertical axis placed on the tablet are 1.
When y is the dimension of the horizontal axis and lX is the dimension of the horizontal axis, a patent characterized by the number of coils being proportional to each length n/11 x
It is expressed as = m/ly oc - phase change rate a, and the value of the above formula is a value proportional to the phase change rate aK.

Here, the condition ah:1 is established for error correction due to the inclination of the pen. Here, h is the effective height of the pen on the tablet surface, and if the pen height is constant, the phase ratio a is also determined to be constant.

When a tablet 414 is constructed according to the above principle, the coil arrangement FI Id is as shown in FIG.

In FIG. 6, the aspect ratio of the tablet is set to m and n, and the same 1 driving IFi signal is energized to the m and n coils.

In this case, when the coil radius is n), the driving current is nA for n coils, and the trace of ~Xn is m3.
By applying a driving current of 1 to 1 m, a tablet with an aspect ratio of m:n is formed.

This makes it possible to read coordinates with uniform precision in the vertical and horizontal directions.

<y) As described in detail of the invention, in the present invention, a processing circuit reads the phase linear range of each of a plurality of tablets, and a wide phase linear range is formed by adding the respective phase linearity ranges. Since it uses a uniform coordinate island even on the tablet, it is possible to obtain the accuracy of 0.

[Brief explanation of the drawing]

Fig. 1 shows a conventional coordinate reading device, Fig. 2 shows a drive coil for a tablet, Fig. 3 shows the connection of a plurality of tablets and their phase characteristics, and Fig. 4 shows the connection and phase characteristics of a tablet according to the present invention. FIG. 5 shows an embodiment of the invention, and FIG. 6 shows another embodiment of the invention. In the figure, 1 and 1' are coordinate reading devices, 2, 3.2', and 3' are tablets, 4 is a switch circuit, 5 is a drive circuit, 6 is a magnetic field detector, 6' is a magnetic field detection coil, and 7 is a phase detector, 8
is a phase/coordinate converter, 9-1 to 9-5.9'-1 to 9'
-5 is the coil, 10 and 11 are the phase linear range, 12°1
3, t4. tm is a phase nonlinear part, 16 is a chain line, 16'
17 indicates a phase junction, 17 indicates a wide phase linear range, 18 indicates a processing circuit, and 19 indicates a memory circuit. 1st m 9'l +',! 113f4 Q
'I't ψ2 ψwo -4ψ5! -Figure 3

Claims (1)

[Claims] A tablet having a plurality of coils arranged in parallel on a plane plate is energized with a plurality of driving signals having mutually shifted phases to each of the plurality of coils, so that the tablet is placed above the tablet according to the position of the tablet. An alternating 3 fm magnetic field generator that forms rotating magnetic fields with different phases, a magnetic field detector located above the tablet that detects the rotating magnetic field, and an output from the magnetic field detector as input to determine the phase of the rotating magnetic field. Detection [2] A processing circuit for reading the position of a force and magnetic field detector placed on the tablet]'L, In a coordinate reading device in which a plurality of tablets are connected and the tablets are driven in a time-division manner, Means for setting the mutual connection points of the fNi tablets to the phase line range of each tablet; and the connection point f: storing and correcting the phase positional relationship of the tablets to obtain a comprehensive phase line range of the plurality of tablets. A coordinate reading device characterized by having means for reading a range.